Wells are generally drilled into a land surface or ocean bed to recover natural deposits of oil and gas, and other natural resources that are trapped in geological formations in the Earth's crust. Testing and evaluation of completed and partially finished well has become commonplace, such as to increase well production and return on investment. Information about the subsurface formations, such as measurements of the formation pressure, formation permeability, and recovery of formation fluid samples, may be useful for predicting the economic value, the production capacity, and production lifetime of a subsurface formation. Furthermore, intervention operations in completed wells, such as installation, removal, or replacement of various production equipment, may also be performed as part of well repair or maintenance operations or permanent abandonment. Such testing and intervention operations have become complicated as wellbores are drilled deeper and through more difficult materials. Consequently, in working with deeper and more complex wellbores, it has become more likely that downhole tools, tool strings, tubulars, and other downhole equipment may become stuck within the wellbore.
A downhole tool, such as an impact or jarring tool, may be utilized to dislodge a tool string or other equipment when it becomes stuck within a wellbore. The impact tool may be included as part of the tool string and deployed downhole or the impact tool may be deployed after the tool string becomes stuck. Tension may be applied from a wellsite surface to the deployed impact tool via a wireline or other conveyance means utilized to deploy the impact tool to generate elastic energy. After sufficient tension is applied, the impact tool may be triggered to release the elastic energy and deliver an impact intended to dislodge the stuck tool string.
If the impact tool is not able to dislodge the stuck tool string, a release tool included along the stuck tool string may be operated to disconnect a free portion of the tool string from a stuck portion of the tool string. The release tool may be operated, for example, by applying tension from the wellsite surface to break a shear pin to uncouple upper and lower portions of the release tool and, thus, the tool string from each other. After the free portion of the tool string is disconnected from the stuck portion, the free portion may be removed to the wellsite surface. Fishing equipment may then be conveyed downhole to couple with and retrieve the stuck portion of the tool string. However, in some downhole applications, such as in deviated wellbores or when multiple bends are present along the wellbore, friction between a sidewall of the wellbore and the conveyance means may reduce or prevent adequate tension from being applied to the tool string and the release tool therein to break the shear pin or otherwise uncouple and separate the upper and lower portions of the release tool and, thus, disconnect the free and stuck portions of the tool string from each other.